Learn how to play slot machines to get the best payback possible. Get the best odds and hit frequency by playing smarter. the denomination is going to play the biggest role in the percentage you get, so start your choice with that. The example I always use to show people a Buy-a- Pay game is the Blazing 7 s by Bally.
Learn about slot machine odds and the probability of winning; including the machine would be a break-even proposition, as on average you'd pay $1.